1. Field of the Invention
This invention relates to a pneumatic radial tire capable of making optimum a deformation and a resistance force of the tire in correspondence to a difference between external forces respectively acting to a front tire and a rear tire and more particularly to a method of mounting a pneumatic radial tire suitable for use in motorcycles and the like.
2. Description of Related Art
There have hitherto been known various structures as a pneumatic tire for a vehicle such as motorcycles and the like. With the maintenance of recent expressways, it is required to ensure a high-speed durability even in pneumatic radial tires for motorcycles. For this end, there are also known tires having a spiral belt extending in a circumferential direction of a crown portion thereof.
And also, there are known a mounting structure that tires having only a spiral belt are mounted onto a front wheel and a rear wheel of a motorcycle, respectively, and a mounting structure that a tire having a combination of a spiral belt with a pair of cross belt members containing cords therein, the cords of which members being crossed with each other, is used only in either a front wheel or a rear wheel of a motorcycle.
However, when the radial tire having the spiral belt and the pair of cross belt members is mounted onto either the front wheel or the rear wheel of the motorcycle, there is no technique that an angle of the cord in the cross belt member is clearly defined with respect to each of the front and rear tires.
In each of the conventional front and rear tires, therefore, the balance of rigidity, ground contact property and generation of lateral force in the tire is not satisfactorily achieved. To this end, the above tires have a drawback that convergence of vibration behavior in a vehicle body as a whole, running performances including cornering force at a corner, gripping limit and slip controlling property are not obtained at sufficiently high levels, respectively.